Hi 067734m
As one of the Admins here i can tell you that you've posted a touchy subject. Most regular members around here are indeed against this device and do not use one, so i'm not sure what positive advice (if any) they might have on this device.

I can say that I have heard many stories of these devices not being able to work in cases where a dog's instinct gets the best of them (like when they see a squirrel or another cat etc).
Adrenaline and instinct often win - so now we are not talking about the ethics of this device, but rather about its efficacy, and ultimately, about your pet's safety if you put too much trust in it. ...

Thanks, Marko. From what I've seen online it is a touchy subject - I'm hoping for constructive comments, like yours:
I have wondered about the "adrenaline/instinct" factor and whether an e-collar would make a difference. I guess there's only one way to find out...

I am open to alternatives, but as mentioned, I have been through a lot of different 'non-e-collar' methods already. Some worked well (some sucked). Maybe 100% recall is an unattainable goal... I'm still going to give it a try!